[ferret_users] Ensemble realization analysis

[Brockmann Patrick <Patrick.Brockmann@xxxxxx>]

Hi all,

Sorry for the uncompleted previous message.

When you analyze ensemble realizations
(read http://cmip-pcmdi.llnl.gov/cmip5/docs/cmip5_data_reference_syntax.pdf
Ensemble menber paragraph), you would like to work with
a variable over its realizations seen as a nth dimension and then apply 
on it power of ferret transformations.

Unfortunatelly, there are only 4 dimensions in ferret.
But sometimes, you also may have the chance that the variable you analyze
has 3 dimensions and has a XZT shape.

I have imagined to use the ZCAT function to concat the XYT variable over 
the Z dimension
and then get a XYZT variable with the Z dimension representing a 
realization dimension.

It seems to work since for one time step I can shade a difference but 
when I plot
a time evolution I get the same plot from the 2 realizations. That is 
not correct.

Try the attached script if interested.

Any share of experience on this topic is welcome. The challenge of 
course is not
to physically save files.

Patrick

--
LSCE/IPSL, Laboratoire CEA-CNRS-UVSQ
Data Analysis and Visualization Engineer
IPSL Global Climate Modelling Group
--

!##############################################
use "http://dods.extra.cea.fr/cgi-bin/nph-dods/data/p86denv/IPSLCM5A/PROD/rcp45/v3.rcp45.1/ATM/Analyse/TS_MO_YE/v3.rcp45.1_20060101_21651231_1Y_t2m.nc";
use "http://dods.extra.cea.fr/cgi-bin/nph-dods/data/p86denv/IPSLCM5A/PROD/rcp45/v3.rcp45.2/ATM/Analyse/TS_MO_YE/v3.rcp45.2_20060101_21001231_1Y_t2m.nc";

!##############################################
show data/full
let a=zcat(T2M[d=1],T2M[d=2])

!##############################################
shade/l=20  a[k=2]-a[k=1]
say It seems ok: there is a difference between realization rcp45.1 and rcp45.2 at time step 20
pause

plot/l=1:40 a[i=@ave,j=@ave,k=2], a[i=@ave,j=@ave,k=1]
say Plots are similar ??